The present disclosure contemplates methods and techniques for extending an existing spinal construct, and more particularly to procedures for achieving such extension minimally invasively, and preferably percutaneously.
An emerging trend in spinal fixation is an increased incidence of adjacent disc degeneration subsequent to a previous fixation or fusion. This subsequent degeneration often requires fixation or fusion of additional levels of the spine. It is common in current techniques to expose the entire prior construct to access all of the existing bone fasteners to permit removal of the connecting member spanning the fasteners. The connecting member is removed and replaced with a longer member, such as a rod, to engage an additional bone fastener added at the new levels to be instrumented.
This exposure of the prior fixation construct disrupts the existing construct complicating and lengthening the surgical procedure for adding the additional level of fixation. Such techniques are particularly problematic for a fixation construct spanning three or more vertebral levels. As such, there is a need for a device and method that facilitates the addition of further levels of fixation.
Several recent advancements have been disclosed that describe the extension of existing spinal constructs with minimal disruption to the existing construct. One example is shown in co-pending commonly assigned U.S. application Ser. No. 12/797,682, entitled “Devices and Methods for Adding an Additional Level of Fixation to an Existing Construct”, filed on Jun. 10, 2010 and published as No. 2010/0318131. Other examples include U.S. Pat. No. 7,976,567, entitled “Orthopedic Revision Connector”, issued on Jul. 12, 2011 to William B. Null, et al. and U.S. Pat. No. 8,021,399, entitled “Rod Extension for Extending Fusion Construct”, issued on Sep. 20, 2011 to Stephen Ritland. While these approaches represent improvements in revision techniques and devices, it would be advantageous to not only extend an existing construct in a relatively non-disruptive manner to such construct, but to do so in a minimally invasively and, preferably percutaneous procedure.